var cookie = {
	//写入cookie
	setCookie:function(name,value) { 
		var Days = 30; 
		var exp = new Date(); 
		exp.setTime(exp.getTime() + Days*24*60*60*1000); 
		document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString(); 
	},
	//读取cookie
	getCookie:function(name) { 
		var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
		if(arr=document.cookie.match(reg))
			return unescape(arr[2]); 
		else 
			return null; 
	},
	//删除cookies 
	delCookie:function(name){ 
		var exp = new Date(); 
		exp.setTime(exp.getTime() - 1); 
		var cval=getCookie(name); 
		if(cval!=null) 
			document.cookie= name + "="+cval+";expires="+exp.toGMTString(); 
	}
};